1. Field of the Invention
The present invention relates broadly to installation of valve stems for tubeless tires, and more particularly to a tool for externally inserting a valve stem into the rim of a tubeless tire assembly.
2. Description of the Prior Art
In recent years so-called tubeless tires have largely replaced the tire and separate inner tube arrangement employed earlier. In the earlier arrangement the inner tube included a valve stem which was adapted to extend through an opening in the rim for inflation of the tube. In the tubeless tire and rim assembly, the inner tube is eliminated and the tire is so constructed as to form an air-tight seal with the rim. A separate valve stem is sealingly seated in the opening in the rim for inflation of the tire.
Such valve stems generally comprise a metal tube disposed within and bonded to a rubber sleeve. The rubber sleeve has at its inner end an enlarged flange or base adapted to sealingly engage at least the interior surface of the rim around the opening as air pressure is applied thereto. The metal tube projects beyond the rubber sleeve at the outer end and is provided with external threads for retaining a valve cap. Heretofore the valve stems have generally been installed by inserting them through the opening from the inside of the rim and pulling them into position from the outside. Various tools are known in the art for installing valve stems in this manner. Such tools as disclosed, for example, in U.S. Pat. No. 3,852,839 to Blessing, generally include an elongated member threaded for attachment to the valve stem and by which the valve stem can be pulled into seated position within the opening in the rim.
In order to install a valve stem in this manner it is, of course, necessary that the tire be removed from the rim, or at least that the tire bead be broken free from the rim to provide access to the interior for insertion of the stem. Demounting and mouting of the tire requires specialized equipment and skilled personnel. In many instances a flat tire is due to failure of the valve stem itself, so that all that is necessary for repair of the tire is installation of a new valve stem. Heretofore it has nevertheless generally been necessary to demount the tire to install the valve stem, resulting in an undue expenditure of time and money. Various tubeless tire valves have been developed with specific configurations for installation from the exterior of the rim as disclosed, for example, in U.S. Pat. Nos. 2,866,492 to Lee, 2,872,963 to Boyer, 3,863,697 to Brown and 4,016,918 to Thacker. Such devices have not proven entirely satisfactory. Furthermore, their use for repair purposes would require that a repair shop carry an inventory of the special repair valves in addition to the standard valves. Thus, it would be highly advantageous to be able to quickly and easily insert standard valve stems from the exterior of the rim. U.S. Pat. No. 3,798,738 to Purtell discloses a device for inserting so-called mushroom drainage valves in irrigation pipe from the exterior of the pipe. The drainage valves are of a completely different construction, so that the device would not be suitable for inserting tubeless tire valve stems in the manner of the present invention.